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THE FEUTEX TOOLKIT

Sewing Dart Pivot Transfer

Transfer a dart angle to a different seam distance from the same pivot while preserving its angular intake.

Crafts workspace● Runs in your browser
01 Your input
02 Your result
View or copy raw result data
FormulaPreserved dart angle = 2*Math.asin(width/(2*radius))*180/Math.PI; New straight opening = width*newRadius/radius; Original tip-to-opening midpoint distance = Math.sqrt(radius**2-(width/2)**2)

Made for real tasks

  • Transfer a dart angle to a different seam distance from the same pivot while preserving its angular intake.
  • Compare a second measured configuration before cutting materials.
Explore step-by-step workflows →

Worked example

Inputs

Original pivot-to-leg endpoint length
15 cm
Original straight dart opening
3 cm
New pivot-to-leg endpoint length
22 cm

Expected results

Preserved dart angle
11.47834095 degrees
New straight opening
4.4 cm
Original tip-to-opening midpoint distance
14.92481156 cm

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Measure a representative sample and enter the values in the displayed units.
  2. Calculate the result, mark a test piece and verify it before cutting the final material.

Try this example

{
  "radius": 15,
  "width": 3,
  "newRadius": 22
}

Accuracy and scope

Ideal flat-pattern dart rotation around one pivot, using equal-length legs and chord widths. True-up seam curves and test garment fit; body shaping and dart-tip shortening are not inferred.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.